darkscout Wrote:It was a case to illustrate a point.

What if you have 3 people watching different things that happen to be on the same hard drives? Something at the beginning of the 1st platter. Something at the middle and something at the end of the 3rd platter?

Technically it should work given that SATA is 3Gb/s. But given you have 3 different clients trying to access 3 different points on he same hard drive at the same time...

froggit Wrote:I can't say for all RAID systems, but with ZFS you can choose your preferred level of redundancy. For example, if you're happy with the capacity of one disk for parity data then you could choose a simple 2-drive mirror, or RAID-Z1. If you want more safety then you can choose double-parity like RAID-Z2. If you want triple-parity then you can choose RAID-Z3, which allows three drives to fail before you lose any data.

So depending on your wallet / paranoia level, you can choose a level of data safety that suits your own situation.

froggit Wrote:Why not use enterprise-level data safety mechanisms that are *free* and available within ZFS? What happens with unRAID if your parity drive dies, or one or two of your data drives dies? With ZFS, using RAID-Z2, if *any* one or two drives die you lose no data, and you can rebuild any dead drives so *no* data is lost.

froggit Wrote:USB sticks are not generally suitable for booting OS's from as they tend to write frequently to the devices (logs etc), and this will reduce the life of the USB stick. They are also fairly slow to boot from.

froggit Wrote:Solaris has corporate support from Oracle.

froggit Wrote:Also, for ZFS newbies there is a great forum available on the OpenSolaris.org site which is frequented by very knowledgeable & helpful ZFS users - see here, including Oracle staffers: http://opensolaris.org/jive/forum.jspa?forumID=80

froggit Wrote:ZFS is simple - here I will create a 6-drive array which can survive any two drives failing before any data is lost:
# zpool create tank RAID-Z2 drive1 drive2 drive3 drive4 drive5 drive6

froggit Wrote:<snip>
Voila, what's hard about that?

Now, for one of the killer features of ZFS, that virtually no other RAID system has -- the ability to find and repair all files that have become corrupt due to 'bit rot':
# zpool scrub tank

This last command will read the contents of *all* files within your storage system and compare each block with a 256-bit block checksum. Any blocks not matching the checksum will be recovered by using the parity data stored when the file was originally created. This feature is priceless and gives you peace of mind that your data is 100% correct as it should be. Can unRAID or FreeNAS do that?

froggit Wrote:Not if the data is in cache. ZFS uses available free memory to store files read.

However, it will need to spin the drives if data is not in cache.

froggit Wrote:However, for energy reduction, you may use the OS power management features to spin-down drives after a set time period like 5 minutes, and a lot of the 'green' drives auto-park heads for reduced power usage anyway.

froggit Wrote:You are very generous. I am not willing to lose any data. And the price of 2 drives to give peace of mind helps me sleep really well. And I have a backup of everything.

froggit Wrote:Read my previous reply about ZFS to get an idea of how easy it is to use and setup, and the data safety mechanisms built in. You can look at parity data a bit like insurance: have no parity data and you lose data when drive(s) die, have parity data and your loss is zero to low, depending on how much parity data you have and how many drives die. It's not rocket science. Once this is understood well, one can plan the level of safety required.

darkscout Wrote:I finally got unRAID running running on VirtualBox (no small feat since mlabel c:UNRAID would add random glyphs to the end "UNRAID". So I had to do label X, edit the bzroot to mount LABEL=X, etc).

darkscout Wrote:I can't explain how unimpressed I am.
I'm running "version: 5.0-beta2."

Under AFP & FTP it lists "Coming soon!". So there goes my TimeMachine backups.

darkscout Wrote:When adding a user I can't specify the UID, so NFS... well must just be global read/write (I'm on my XP laptop at work so no proper NFS).

(I know you can do "user shares") but by default all I see are "disk1" and "disk2" folders.

darkscout Wrote:I swapped out one of my virtual 10GB drives for a virtual 20GB drive (The scenario you keep repeating). I instantly got the error "Stopped. Disk in parity slot is not biggest." "If this is a new array, move the largest disk into the parity slot. If you are adding a new disk or replacing a disabled disk, try Parity-Swap." Except I can't find the Parity-Swap button.

darkscout Wrote:I also notice that all my data isn't there. Isn't the parity drive just supposed to the missing data? I mean with ZFS I just do a disk swap and I have full coverage, in the mean time NONE of my data is missing.

darkscout Wrote:Fine. Power down. Put the 20GB drive into the parity disk slot... still have only 20GB available (disk1 & disk2).

darkscout Wrote:At which point I get the fun message "WARNING: canceling Parity-Sync will leave the array unprotected!" For another 37 minutes. Meaning if a drunk driver hits a power line, neighbor digs into his power, who knows what else could happen: my data is unprotected.

darkscout Wrote:The Free version only supported 2 disks (3 if you count parity). Free version of NexentaStor supports up to 12TB.

darkscout Wrote:I suppose if I wanted to slap a bunch of drives in a case and have a NAS for unimportant stuff, maybe... then again I'd have to pay for using more than 2 drives. So I'd go with FreeNAS.... at which point I'd just use ZFS.

PANiCnz Wrote:I hate to fire up an already heated debate but everyone also seems to be ignoring the performance benefits that ZFS has, especially with coupled with ARC and L2ARC. When researching unRAID I'm pretty sure its widely acknowledged performance isn't great.


I think its might just be a case of us three being the only ones who've taken the time to read all the ZFS articles on the net and fully understand them.

I agree that ZFS realtime checking to guard against bitrot is probably one of its biggest selling points, until you've seen a few hundred gigs of data slowly corrupt without your knowledge you won't truly appreciate it.

unRAID is just JBOD with parity, I guess it serves its purpose.

GJones Wrote:Which is horrible, since you are commenting on the lack of quality of community support on the community support forum for another piece of software.

Quote:I've seen few people have a problem with unRAID: buy hardware that is certified and it works. I've asked quite a few questions along the way and never had to wait more than an hour or two to get not just an answer but the correct one.

BLKMGK Wrote:So if I choose a single parity drive and two drives fail what's left? What data recovery tools do I have available for the drives that failed and I pulled? How many drives worth of data did I have to sacrifice in your example? Must all of those drives be spinning for me to watch a movie?



If my parity drive fails I lose no data. If I lose TWO drives I lose two drives worth of data but can use standard repair tools or services to recover them. If I lose a parity drive and a data drive I lose one data drive worth of data. You don't understand how unRAID works do you? It shows.




My USB stick isn't written to during a normal course of operation and I reboot my server maybe once every couple of weeks to months - it boots in about 2minutes. I lose ZERO storage space to my OS which boots from a USB stick. I take it you're telling me that's not the case for you?



Solaris X86 is corporately supported still?



Umm, unRAID is supported by folks too including the guy who wrote the software. Mind you the forum is dedicated mostly to folks using the software to run a NAS and not a general OS.



How much data space are you losing for that level of redundancy? Must all drives be spinning if I watch a movie? ZFS spans drives right?



I guess my question is do I need it to do that? Yeah, I CAN run a parity check and I CAN get data errors corrected. Mine runs monthly as I recall. How much space are you dedicating to storing that checksum?

Look, my needs are pretty simple. I store mostly video and I want to use as much disk space as possible while using as little electricity as possible. I want the array to be fast enough to stream my data and I want it to be able to suffer the inevitable drive failure. For the fool who calls those of us using this system "fanboys" for defending it it's pretty apparent you don't understand the fact that this system meets all of or needs and has in my case for something like 5 YEARS now.

BLKMGK Wrote:I DO have parity data. I am willing to use one disk to store parity for all of my disks. So if I have 15 data disks I am using ONE parity disk.

froggit Wrote:Thanks for the entertainment - very amusing

So:
- you hate the idea of spending money on spinning disks up
- you hate the idea of spending money on buying one extra disk*

but:
- you like to spend money on something like unRAID which has inferior data protection
- you like to spend money on leaving your unRAID NAS on 24/7

Thanks for clearing that up.

*The money you refused to spend on one extra disk will result in a 2 drive failure losing you 2 drives worth of data (movies).

My system would lose no data but yours loses 2 drives of data. I can see now why you love unRAID

froggit Wrote:Man, this bit made me die laughing...



I take it all back... you are not generous at all.

If you had one parity disk for 15 data disks I think you would:
a. Put Ebeneezer Scrooge out of business
b. Would be taking a ridiculous gamble with your data.

I wish you luck, you'll probably need it, or at least a lot of time to spend attempting to recover your data when those drives get cranky. And just imagine all that bit rot goodness...

gadgetman Wrote:Why bother debating over this?
Who cares if someone even store their media on twenty 80GB USB drives connected thru USB 1.1 hubs, setup with windows JBOD?

Seriously though, I run 2 storage servers at home: a 12TB zfs on a freenas, and a 27TB unRAID.

Guess which one is for my media?

The zfs machine is used for ip camera and personal backup system where I need the highest performance and I want to avoid any bitrots and immediate access.

unRAID is just GREAT for building a media cabinet. I started out with something like 4TB a few years ago and slowly added a drive at a time to expand the unRAID volumes. None of the original drives were used anymore, yet the original data and drive/volumes are still the one used; except expanded thru more than a dozen steps. I have a few email triggers on it (temperature, SMART checks, and daily reports) to avoid such slim catastrophe like 2 drives failing; but if that happens I could just rerip the data on just those 2 drives. No big deal, the benefit far outweigh the cons for me.

Horses for courses.



Are you guys talking about media server or something to hold much higher valued commodities?

Do you expect people to take you seriously with all those ignorant and derisive remarks?

froggit Wrote:So:
- you hate the idea of spending money on spinning disks up
- you hate the idea of spending money on buying one extra disk*

froggit Wrote:My system would lose no data but yours loses 2 drives of data. I can see now why you love unRAID

markguy Wrote:I think it would be awesome if this thread could stay above a schoolground level of maturity. I don't see anyone flocking to a particular solution based on what's being displayed here, frankly.

One of the things that concerns me most about the ZFS solution is the part of Simon's blog described as RAIDZ expansion. If I have 14TB of data, I have to have at least 28TB of storage to increase the size of the storage pool. Actually, it's 28TB, plus whatever you want to grow the pool by. I'd have a hard time justifying buying, building and managing a spare box just to keep a spare, empty 14TB of space around.

To someone like me, who uses unRAID, but is interested in ZFS's robustness, it seems a better idea might be to have two boxes, an unRAID box for replaceable media rips that grows pretty effortlessly as needed and another using ZFS for storing irreplaceable documents, photos, to-do lists (which my wife claims are critically important).